Step 1Combine sugar and water in saucepan and bring to boil. Cook until clear, about 1 minute. Remove from heat and cool. Cover syrup and chill 1 hour or until ready to use.
Step 2Cut off 6-pound piece of watermelon and, using melon scoop, form melon balls. Place in covered container and chill until party time.
Step 3Cut fruit from remaining rind and puree. You should have about 8 cups puree. Cover and chill 1 hour or until party time.
Step 4To make drinks, fill each glass 2/3 full with watermelon puree, 2 tablespoons simple syrup or to taste, 1 tablespoon lemon juice and 1 shot tequila, if desired. Add a few ice cubes and top off glass with club soda. Stir in several watermelon balls.